'B 51 
B29 
opy 1 



f 




EMBRACING 



ITS SUBLIMITY, HISTORY, PROGRESS, 
WONDERS AND UTILITY. 



A POPULAR LECTURE. 



BY ARTHUR K, "BARTLETT, 




BATTLE CREEK, MICH. 



1877. 




THE 



SCIENCE OF ASTRONOMY, 



v 



EMBRACING 



ITS SUBLIMITY, HISTORY, PROGRESS, 
WONDERS AND UTILITY. 



A POPULAR LECTURE. 



BY ARTHUR K. BARTLETT. 



A 



>> I 



" I shall straight conduct you to a hill- side, laborious indeed at the 
first ascent ; but else so smooth, so green, so full of goodly prospect 
and melodious sounds on every side, that the harp of Orpheus 
not more charming."— Milton. 



: 



■5 HiJjoj : 



REVIEW & HERALD BOOK AND JOB PRINT, 

BATTLE CRBEK, MICH. 

1877. 






TO 
MY FATHER, 

(tarte* & gatttett, gl §., 

Whose sympathy and encouragement in niv scien- 
tific studies will ever be appreciated, and 
in which I have found my constant 
inspiration and success, 

THIS LITTLE PAMPHLET IS 

AFFECTIONATELY fiEOICATE®. 
As a Slight Tokex or Gratitude. 



Copyright, 1877, by Arthur K. Bartlett. 



y 



T^e $ciende of ^tfoi\orqy. 



"The heavens declare the glory of God; and the firmament 
showeth his handiwork." Psalm xix, 1. 

LADIES AND GENTLEMEN : The theme which 
I have chosen for my lecture is not only sublime, 
but one of stupendous magnitude. I intend to speak 
upon the general subject of astronomical science, — 
its sublimity, its history, its progress, its wonders, its 
utility, and its encouraging prospects for still further 
advancement in the distant future. If those present 
will but give me their earnest and unbroken attention, 
while I introduce them in succession to the grand 
truths of astronomy, my task will be a pleasant one. 
Astronomy is the most ancient of all sciences. The 
study of the stars is doubtless as old as man himself, 
and hence neither history nor tradition can inform us 
concerning the first discoveries in this sublime science. 
Astronomy is a study which has, in all ages, engaged 
the attention of the most learned men of the world. 
" Kings have descended from their thrones to render 
it homage, and have sometimes enriched it with their 
labors ; aDd humble shepherds, while watching their 
flocks by night, have beheld with rapture the blue 
vault of heaven, filled with its thousands of shining 
orbs, moving in silent grandeur, until the morning 
star announced the approach of day." There is prob- 
ably no human being, who, for the first time, has 
turned his eyes toward the nocturnal sky, and beheld 



4 The Science of Astronomy : 

the moon " walking in brightness " among the hosts 
of stars and planetary orbs, marking off the hours, 
minutes, and seconds, with an accuracy which no 
clock can ever rival, but must have been struck with 
awe and admiration at the splendid scene. 

Who has not looked up to the celestial vault on a 
calm, bright night, " when all the stars shine, and the 
immeasurable heavens break open to their highest," 
and said to himself, " What are these far-off lights"? 
Are they worlds similar to our own, or merely lights 
placed in the heavens by some invisible being, for the 
purpose of exciting our reverence and admiration? 
What are their distances from our earth, and are they 
governed by the same laws which characterize the 
world we inhabit 1 If these are worlds, can they be 
peopled by wise and intelligent creatures like our- 
selves ; and does the Almighty rule over their destiny 
as he does our own? These, and similar questions, 
will naturally present themselves to all persons who 
allow their thoughts to soar among the star-depths. 
Even the little babe, in its weak and punny mind, 
looks up to the starry heavens and perceives the 
beauties which they disclose, while filled with wonder 
and admiration. Many persons ask if these great 
celestial mysteries will ever be revealed to us, while 
others seem wholly unconcerned about them. A 
large number of these grand problems have already 
been solved, while others yet await the patient astron- 
omer, whose keen eye, in generations to come, shall be 
able to read the mysteries therein. The heavens are 
before us, inviting our study, and waiting to make 
known unto us the grandest revelations of science. 

Some enthusiastic writer has made the following 
truthful remark : " Perhaps there is no subject upon 



.1 Popular Lecture. * 5 

which the people are so profoundly misinformed as 
that of astronomy. Night after night they gaze up 
into the starry depths with as much intelligence as 
they would bestow upon a spangled wall-paper, — in 
fact, a degree less ; for in the one case they know 
that they are spangles, and in the other they gaze on 
beautiful vacancy." The best reason known why so 
few persons care to study astronomy, is because the 
heavenly bodies can be so easily observed upon a 
clear sky. Prof. Henry Whitall, of New York, the 
inventor of the well-known " Movable Planisphere " 
so extensively used in the United States, makes the 
following true and interesting remark : "If there 
was but one spot on the earth where the gorgeous 
heavens were visible, and that a small place no larger 
than the State of New Jersey, there would not be a 
college in our land that would dare to graduate a 
pupil without that pupil being able to describe the 
wonders within that little State ; and the education 
of no pupil would be considered complete until he 
had made a visit to see the beautiful stars which 
were visible on a clear evening within that little 
place." Because all can behold for themselves the 
starry heavens spread out to their view, is the prin- 
cipal reason why so few care to become acquainted 
with what all may see and know. The earth has the 
gift of captivating us so strongly, that we willingly 
forget the heavens for it. If sometimes we allow 
ourselves to be exalted by the wonders of the skies, 
we quickly return to the things of earth, forgetting 
our grand celestial questions. 



6 The Science of Astronomy : 

" Wben morning sheds its gorgeous dye, 
Our hope, our heart, to earth is given ; 
But dark and lonely is the eye, 

That turns not, at its eve, to heaven." 

Nothing is more grand, more awe-inspiring, than 
the contemplation of the starry heavens. The study 
of the stars is the most ennobling within the range of 
speculative science. The mind that rises to the 
skies seems to soar above the littleness of earthly 
things, and in communing with the wonders of ap- 
parently silent but everlastingly rolling nature, one 
becomes purified, elevated, and in every way nearer 
to "the fear of God 9 " which "is the beginning of 
wisdom." Concerning the sublime and inspiring as- 
pect of astronomy, Prof. Richard A. Proctor, the 
eminent English astronomer, very eloquently remarks, 
while referring to the beauties of the starry heavens : 
" The mind cannot but be strengthened and invigor- 
ated, it cannot but be purified and elevated, by the 
contemplation of a scene so full of magnificence, im- 
perfect though the means be by which the won- 
ders of the scene are made known to us. The infor- 
mation given by the telescope is indeed but piecemeal, 
and as yet no adequate attempts have been made to 
bring the whole array of known facts as far as pos- 
sible into one grand picture ; but seen as it is, only by 
parts, and (even so) only as though a vail and darkly, 
the scene presented to the astronomer is the grandest 
and the most awe-inspiring which man can study." 

The starry heavens present an aspect which has been 
admired for its beauty by the poets, in all ages. Thus 
Byron : — 



A Popular Lecture. 7 

u Ye stars! which are the poetry of heaven, 
If, in your bright leaves, we would read the fate 
Of men and empires,- — 'tis to be forgiven, 
That in our aspirations to be great, 
Our destinies o'erleap their mortal state, 
And claim a kindred with you ; for ye are 
A beauty and a mystery, and create 
In us such love and reverence from afar, 
That fortune, fame, power, life, have named themselves 
a star." 

Every person should possess a certain knowledge 
of the starry heavens. It was the regret of Thomas 
Carlyle that no one had ever taught him the beautiful 
constellations. How many a man can say the same 
to-day ! What person would not exclaim with the 
poet Virgil, 

"Give me the ways of wandering stars to know, 
The depths of heaven above, and earth below." 

Few persons can realize the great work which is 
being performed by astronomers in various parts of 
the world. Go to some large observatory at night, 
and if you are a favored visitor, you shall peep in at 
the solitary explorers of the universe, as they sit, in 
separate apartments, perched high upon curious lad- 
ders, or crouched in quiet corners. Their eyes are 
glued to apertures which are the windows looking 
out upon the infinite. When obscuring clouds do not 
sweep across their field of vision, they will remain 
whole nights rooted to their places, pausing only to 
shift their machinery, or to jot a few memoranda, un- 
til the kindly light of morning drives their beloved 
stars from sight, and themselves to their repose. 
While the world sleeps around them, they pore, and 
strain, and study night after night, year after year. 
Proud to contribute their mite to the fund of the 



8 The Science of Astronomy : 

world's information, they will lay them down to their 
final rest, happier than emperors, if they have but dis- 
covered some few new planets, or more clearly demon- 
strated the character and movements of the older ones. 
Many of these " star-gazers " have bent over their 
books and machines until they have grown gray in 
their work, and extreme old age is now upon them. 

Most persons would naturally suppose that a study 
which requires such constant attention, often robbing 
the astronomer of his peaceful hours of slumber and 
repose, would somewhat abridge the period of life. 
But astronomers, as a class, are noted for their lon- 
gevity, and generally outlive all other men. It is a 
remarkable fact, well worthy of notice, that distin- 
guished astronomers most often die between the ages 
of seventy and eighty-five. Sir William Herschel, 
the greatest " star-gazer " of modern times, died at 
the advanced age of eighty- three ; and Lalande lived 
to the same age, who, it is said, was wont to remain 
whole nights in his attic for the purpose of studying 
the stars and planets. The late Sir John Herschel 
died at the age of seventy-nine ; and Prof. Airy, the 
eminent Astronomer Royal, of England, is still living 
at a "ripe old age." Prof. Olmsted, of Yale College, 
says : "I know not how to account for this fact, un- 
less we suppose that the study of astronomy itself has 
something inherent in it, which sustains its votaries 
by a peculiar aliment." 

Every person who pursues this sublime study can 
read a noble lesson in the distant skies. But those 
who receive their knowledge of astronomy merely sec- 
ond-handed are unable to fully realize the grand truths 
which the heavens unfold to professional astronomers 
in their great observatories. Prof. Agassiz, the emi- 



A Popular Lecture. 9 

nent old scientist, now gone to his reward, has made 
the following impressive remarks : " The glance at the 
moon, or at Jupiter's satellites, which the chance vis- 
itor at an observatory is allowed to take through the 
gigantic telescope, reveals to him nothing of the in- 
tense concentrated watching by which the observer 
wins his higher reward. The nightly vision of the 
astronomer, revealing myriad worlds in the vague, 
nebulous spaces of heaven, is not for him ; he must 
take the great results of astronomy for granted, since 
no astronomer, capable of original research, has the 
time to prepare for the uninitiated the attendant cir- 
cumstances essential to his more difficult investiga- 
tions, or to train their eyes to see what he sees." 

Nothing can be more interesting in astronomical 
science than to trace its history and wonderfully rapid 
progress. For a long period, during the infancy of 
this science, comparatively little was known of the 
celestial bodies excepting their apparent motions and 
aspects. Instead of investigating with care their true 
motions and relative distances and magnitudes, many 
of our ancestors looked up to the sky either with a 
brute, unconscious gaze, or viewed the heavens as a 
book of fate, in which they might read their fortunes, 
and learn, from the signs of the zodiac, and the vari- 
ous aspects of the planets, the temperaments and des- 
tinies of men, and the fate of empires. Even to this 
day, and in our own civilized country, the foolish art 
of " casting a horoscope," and prognosticating fortunes 
by the stars, is one of the principal uses to which the 
science of the heavens is applied. 

The subject of astronomy is so vast that it cannot 
be dealt with in a single lecture ; and in tracing the 
history of this science, I shall speak only of those 



10 The Science of Astronomy : 

most important facts which will best enable my audi- 
ence to understand its progress and glorious achieve- 
ments. Prof. O. M. Mitchell, the celebrated astrono- 
mer, who erected, at Cincinnati, the first observatory 
of any importance in the United States, and died in 
the defense of his country, has thus pictured, in elo- 
quent language, the first view of the starry heavens : — 
" Often have I swept backward, in imagination, six 
thousand years, and stood beside our Great Ancestor, 
as he gazed for the first time upon the going down of 
the sun. What strange sensations must have swept 
through his bewildered mind, as he watched the last 
departing ray of the sinking orb, unconscious whether 
he should ever behold its return. Wrapt in a maze 
of thought, strange and startling, his eye long lingers 
about the point at which the sun had slowly faded 
from his ^iew. A mysterious darkness, hitherto un- 
experienced, creeps over the face of nature. The 
beautiful scenes of earth, which through the swift 
hours of the first wonderful day of his existence, had 
so charmed his senses, are slowly fading one by one 
from his dimmed vision. A gloom deeper than that 
which covers earth, steals across the mind of earth's 
solitary inhabitant. He raises his inquiring gaze 
toward heaven, and lo ! a silver crescent of light, 
clear and beautiful, hanging in the western sky, meets 
his astonished eye. The young moon charms his un- 
tutored vision, and leads him upward to her bright 
attendants, which are now stealing one by one from 
out the deep blue sky. The solitary gazer bows, and 
wonders, and adores. The hours glide by — the silver 
moon is gone — the stars are rising — slowly ascending 
the heights of heaven, and solemnly sweeping down- 
ward in the stillness of the night. The first grand 



A Popular Lecture, 11 

revolution to mortal vision is nearly completed. A 
faint streak of light is seen in the east — it brightens — 
the stars fade — the planets are extinguished — the eye 
is fixed in mute astonishment on the growing splendor, 
until the first rays of the returning sun dart their 
radiance on the young earth and its solitary inhabi- 
tant. To him ' the evening and the morning were the 
first day."* 

What a grand, imaginary description of man's 
first view of the starry heavens ! But, let us now see 
what the human mind has accomplished in its long 
and patient struggle of six thousand years. Genera- 
tion after generation has passed away, age after age 
has swept silently by, but each has swelled, by its 
contribution, the stream of astronomical discovery. 
There is reason to believe, that astronomy was stud- 
ied by the antediluvians. It is certain that this sci- 
ence was cultivated in Western and Central Asia, 
within two or three centuries after the flood. Xoah, 
probably, communicated some knowledge on the sub- 
ject to his descendants. T la ere was an ancient tradi- 
tion that the patriarch, Abraham, was somewhat ac- 
quainted with this science ; and it is evident that Job, 
a little later, was not ignorant of it, as may be seen 
from the Scriptures. History also informs us that 
the people of India understood astronomy, to some ex- 
tent, eighteen hundred years before the Christian era. 
But the first careful observers of the heavens were the 
ancient shepherds, who, as they watched their flocks 
at night beneath the celestial canopy, naturally be- 
came interested in the orbs with which it was studded, 
and gave names to those that were most conspicuous. 
They knew, however, only such isolated facts as were 
apparent to the eye. It was reserved for later years 



12 The Science of Astronomy : 

to trace visible effects to their causes, and to advance 
theories ; and not until the improved instruments of 
comparatively recent times extended the field of hu- 
man vision almost beyond belief, was it possible to 
penetrate the mysteries of the heavens to their 
depths. 

In this enlightened age of the world, the ideas of 
the ancients respecting the starry heavens appear ab- 
surd, and almost incredible, and we can hardly under- 
stand how they could have been seriously entertained. 
The Chaldeans and Egyptians were the first to make 
any material progress in astronomy, and they were 
particularly distinguished for the accuracy and extent 
of their observations. The former, by continued ob- 
servation, discovered that the eclipses of the moon re- 
cur in the same order, at intervals of eighteen years, 
and were thus able to predict them with considerable 
accuracy ; the latter investigated the motions of the 
planets, and established a sacred year of 365^ days. 
The Chinese, also, paid great attention to this science 
in very early times, and these people boast much of 
their astronomical discoveries. They have the earli- 
est record of a solar eclipse, which occurred about 
220 years after the flood. More than 2300 years be- 
fore the Christian era (according to their own records), 
a tribunal was established for the prosecution of astro- 
nomical studies, and particularly for the prediction of 
eclipses ; and it is reported that one of their kings 
actually put to death his two chief astronomers be- 
cause they had failed to calculate an approaching 
eclipse of the sun. 

From Egypt, the cradle of learning, art, and science, 
the Greeks obtained their first knowledge of astronom- 
ical science. Thales, about 600 years before Christ, 






A Popukui Lecture. 13 

taught that the world was round, and that the moon 
shone by reflected light, borrowed from the sun. 
11 He introduced the division of the earth's surface 
into zones," and first propounded the theory of the ob- 
liquity of the ecliptic. He also established the first 
school of astronomy in Greece. Anaximander, one 
of his pupils, conceived the bold idea that the planets 
are inhabited. Pythagoras, a little later, first con- 
ceived a system of the universe, which was in many 
respects correct ; and he is said to have advanced the 
idea that the planets revolved round the sun. But 
he advanced no proof in support of his views, and 
they were soon well-nigh forgotten. Among other cel- 
ebrated Greek astronomers were Eratosthenes, who de- 
vised an accurate method for measuring the circumfer- 
ence of the earth, and Hipparchus. who calculated the 
length of the year to within^six minutes, discovered 
the precession of the equinoxes, and made the first 
catalogue of all the stars visible above his horizon — 
1081 in number. Ptolemy, an eminent Egyptian as- 
tronomer, who flourished in the second century after 
Christ, rejected the theory of Pythagoras respecting 
the Solar System, and advanced one of his own. which 
soon met with general acceptance. He taught that 
the earth was the center of a system of eight immense 
hollow spheres of crystal, placed one within another ; 
that the moon was in the nearest sphere ; Mercury in 
the next ; Venus in the third ; the sun in the fourth ; 
Mars, Jupiter, and Saturn in the fifth, sixth, and sev- 
enth respectively : and that the eighth belonged to 
the stars, which, though most distant, were still vis- 
ible through the transparent crystal. The revolution 
of this cumbrous system around the earth from east 
to west, once in twenty-four hours, he thought would 



14 The Science of Astronomy : 

account for the succession of day and night and the 
various phenomena of the heavens. 

During the Dark Ages, when every man was his 
own astronomer, this science was cultivated chiefly by 
the Arabians, who made no advance as regards theory, 
but were diligent observers, and devised some im- 
provements in instruments and methods of calcula- 
tion. Even after the termination of this period, com- 
paratively little progress was made until the time of 
Copernicus, a German priest, about 355 years ago. 
He ventured to reject the system of Ptolemy, which 
was still taught in all the institutions of learning in 
Europe, and reviving the teachings of Pythagoras, set 
forth what is called the " Copernican System," now 
very generally received as true by astronomers, al- 
though at first bitterly denounced as visionary and 
even irreligious. " For over forty years, this illustri- 
ous astronomer carried on his observations in the up- 
per part of a humble, dilapidated farm-house, through 
the roof of which he had an unobstructed view of the 
sky. The work containing his theory was finally pub- 
lished just in time to be laid upon his death-bed." 
The three fundamental points of the " Copernican 
System," are : First, that the earth is round ; sec- 
ond, that it turns upon its axis from west to east ; 
and, third, that the earth, and all the other planets, 
revolve around the sun as a center. • 

After Copernicus came Tycho Brahe, a celebrated 
Danish astronomer, who propounded a theory in mod- 
ification of the " Copernican System," and believed 
with Ptolemy that all the celestial bodies revolved 
about the earth as a center, in circular orbits, from 
east to west, every twenty-four hours. This astron- 
omer had a pupil named Kepler, who rejected the the- 



A Popular Lecture. 15 

ory of his master, and advocating that of Copernicus, 
finally enunciated three grand truths of planetary 
motion, known as " Kepler's Laws," — the result of 
eighteen years' assiduous and close observation. 
These three laws are the foundation of our astronom- 
ical knowledge, and form one of the most glorious 
achievements of the human mind. When Kepler 
fully realized the vast importance of his discoveries, 
he was completely overwhelmed with emotion, and at 
last, in the wild excitement of his glorious triumph, 
the great philosopher of the heavens exclaimed : 
" Nothing holds me. I will indulge my sacred fury ! 
If you forgive me, I rejoice ; if you are angry, I can 
bear it. The die is cast. The book is written, to be 
read either now or by posterity, I care not which. It 
may well wait a century for a reader, since God has 
waited six thousand years for an observer !" 

Contemporary with Kepler was the celebrated Ital- 
ian astronomer Galileo, who invented and first used 
the telescope, with which he was enabled to make 
many brilliant discoveries, all tending to support the 
theory of Copernicus. He directed his telescope 
toward Jupiter, and discovered four satellites accom- 
panying this planet in its revolution around the sun, 
— a beautiful " Copernican System " in miniature, 
hung up in the heavens for all to see and examine for 
themselves. Who has not heard of 

" The starry Galileo with his woes? " 

The discoveries of this great astronomer met with the 
most bitter opposition. Because he believed that the 
earth revolved around the sun, and turned upon its 
axis, he was obliged to appear at Home, and answer 
before the Inquisition for his seemingly absurd ideas. 



16 The Science of Astronomy: 

It was there that Galileo, a feeble old man of seventy 
years, kneeled down before the Cardinals, and, with 
his hand upon the Bible, deolared that he " abjured, 
detested, and abhorred the heresy of the earth's motion 
around the sun." But, as the old, gray-headed phi- 
losopher tottered out from the presence of the tribu- 
nal, he is said to have muttered to himself, " The 
earth does move, nevertheless." This is now an evi- 
dent fact, and so the whole world believes to-day. 

The day on which Galileo died was memorable for 
the birth of Sir Isaac Newton, who discovered the 
grand law of "Universal Gravitation," which ex- 
plained the planetary motions. Other astronomers 
had prepared the way, and it was reserved for New- 
ton to make this important discovery, which gave a 
new impetus to astronomical science • or, in the words 
of the poet : — 

*' Nature and Nature's laws lay hid in night: 
God said, ' Let Newton be/ and all was light." 

After all the brilliant discoveries had been made 
in relation to the Solar System, nothing was more dif- 
ficult for the ancient astronomers to explain than the 
apparent motions of the planetary bodies. If the po- 
sition of any planet among the stars be carefully ob- 
served from night to night, it will be noticed that it 
does not always move in one direction through the 
heavens, but will sometimes be observed to direct its 
motion toward the east for a certain period of time, 
and then suddenly halt in its course, remain stationa- 
ry for a while, and begin to move in retrograde order 
toward the west, continuing in that direction until it 
will again come to a very sudden stop, and then, after 
remaining without the least apparent motion for an- 



A Popular Lecture. 17 

other short interval, commence to retrace its course 
toward the east as before. Such are the apparent 
movements of these far-off worlds as observed from 
the earth. All the planets revolve around the sun in 
one direction, — from west to east. Why, then, do 
they sometimes appear to move over the sky, from 
west to east, then halt and remain stationary, and af- 
ter a short interval, direct their course toward the 
west, contrary to the direction in which they at first ap- 
peared to move 1 This is a question which, for many 
generations, puzzled and perplexed the ancient readers 
of the sky. They knew very well (as taught by old 
Copernicus) that the planets moved about the sun as 
a center, and also in the same direction; but the 
most intelligent and best informed of the ancient as- 
tronomers, could not explain the peculiar and com- 
plicated movements of the planets as observed from 
our earth. Their knowledge of the heavens slowly 
increased, and it was finally surmised that the pecul- 
iar and unexplained motions which characterized the 
planetary bodies were owing to the fact that we did 
not observe them from the center of their orbits, but 
from the earth, which was also constantly shifting its 
position in space, and causing them to move with ap- 
parent irregularity through the shy. These were their 
views, and they have since been demonstrated to be 
correct. If, then, we could observe the planets from 
their center of motion — the sun — we should perceive 
these bodies moving around us at various distances, 
but all in the same direction, — from west to east. 

Having thus traced the history and progress of an- 
cient astronomy, let us now consider some of the mod- 
ern discoveries in this science, which clearly illustrate 
the ability of man to grapple with the grand problems 



18 The Science of Astronomy : 

of the skies. There is nothing more encouraging in 
the history of astronomical science than the remarka- 
ble success which has rewarded the observations of 
modern astronomers. From the earliest ages, the 
mighty orbit of the planet Saturn was supposed to 
form the boundary of the Solar System. The slow 
and majestic motion of this planet, its great period 
and distance, and the wonderful magnificence of its 
rings and moons, seemed to render it a fitting object 
to guard the frontiers of the mighty system with 
which it was associated. But, it is a well-known fact, 
as the result of Newton's grand discovery, that all the 
planets exert an attraction upon each other, and pro- 
duce certain orbital disturbances, which are called per- 
tubations. Near the close of the eighteenth century, 
when the planetary motions had been observed with 
great care, and a comparatively accurate knowledge 
of their pertubations had been acquired, certain unex- 
plained motions of Saturn gave rise to the belief that 
another planet revolved around the sun in a vast orbit 
far beyond that of Saturn. On the 13 th of March, 
1781, while Sir William Herschel was engaged in ex- 
amining some stars in the constellation Gemini, his 
attention was attracted to a small star of remarkable 
appearance, which fortunately happened to pass into 
the field of his great telescope. He examined the 
strange star with higher magnifying powers, when it 
appeared greatly increased in dimensions, and exhib- 
ited a sensible disk. After watching it for several 
evenings, Herschel noticed that its position changed 
among the stars, and not even dreaming that the body 
was a planet, he announced to the world that he had 
discovered a new and remarkable comet. But it re- 
quired only a few months go convince the astronomical 



A Popular Lecture. 19 

world that the body in question was a member of the 
Solar System. It is now known as the planet Ura- 
nus, represented in the illustration* before you as the 
seventh in order of distance from the solar orb. 
This planet is situated at a mean distance of 1,754,- 
000,000 miles from the sun, and requires eighty-four 
of our years to complete its vast circuit around that 
luminary. Here is a brilliant astronomical discovery, 
which may be regarded as the result of a merely acci- 
dental observation. 

We will now consider a still more remarkable dis- 
covery, which is regarded as one of the most glorious 
achievements of the human mind. For many years 
after the discovery of Uranus, the movements of this 
planet were such as to baffle the most accurate calcu- 
lations. While the planet Saturn came around to its 
place true to the minute and second, even after its 
journey of nearly thirty years, it was found that the 
planet Uranus did not strictly conform to the path 
assigned to it. It was finally suggested by several 
astronomers that another planet revolved around the 
sun outside the orbit of Uranus, which disturbed the 
movements of this planet, and produced its perturba- 
tions. The disturbing influence of Jupiter and Sat- 
urn, the only planets which could affect the motions 
of Uranus appreciably, had been taken into account ; 
and the masses of these planets had been far too satis- 

* In delivering this lecture, the subject was illustrated with 
large oil paintings, and although the original references are re- 
tained, it has been thought unnecessary, in preparing the lecture 
for publication, to introduce diagrams, as some alterations have 
been made which will doubtless render the explanations clear 
without them. 



20 The Science of Astronomy : 

factorily ascertained to leave any doubt as to the ef- 
fects which they could produce on Uranus. Sir Will- 
iam Herschel had carefully studied the movements of 
Uranus, and so firmly did he believe in the existence 
of another planet, more remote from the sun, that he 
remarked : " We see it as Columbus saw America 
from the shores of Spain. Its movements have been 
felt trembling along the far-reaching line of our an- 
alysis, with a certainty not far inferior to occular 
demonstration." 

It is one of the most difficult problems presented 
to an astronomer, "to determine the motions of a 
planet when all the circumstances which can affect 
that motion are known." The great problem pre- 
sented to the astronomer was this : " Given the dis- 
turbances produced by the attraction of an unknown 
planet, to find its orbit, and its place in the orbit." 
Only two astronomers in the world were bold enough 
to attempt the solution of this problem. These two 
were Leverrier, of France, and Adams, of England, 
both young mathematicians, who, each unknown to 
the other, undertook the task of finding the place of 
the supposed planet. Leverrier was not quite un- 
known to science in his own country, although com- 
paratively at the beginning of his astronomical career. 
Adams was a scientific student of unusual ability, 
and was preparing to receive his degree at Cambridge 
University. None but the professional mathemati- 
cian and astronomer can fully realize the magnitude of 
the problem which was presented to these young men 
for solution. Adams first completed his calculations, 
after nearly two years of toilsome labor, and in Oc- 
tober, 1845, he submitted them to Prof. Airy, the 
Astronomer Royal of England. A few months later, 



A Pop (dar Lecture. 21 

Leverrier presented his calculations to the Academy 
of Science in Pans, and announced the figure of the 
orbit of the supposed planet, its distance from the 
sun, its period of revolution, and even the mass of 
matter which it contains. On the 23d of September, 
1846, Leverrier wrote to Prof. Galle, of Berlin, for as- 
sistance in searching for tne imaginary planet, and 
requested him to direct his great telescope to a certain 
point in the heavens. Prof. Galle, on that same even- 
ing, did as requested, and after a few moments' ob- 
servation, he discovered a star of the eighth magni- 
tude, which he knew to be a stranger in that region 
of the heavens, as it was not laid down on the most 
accurate maps. This proved to be the predicted 
planet, which was discovered within less than two 
diameters of the moon's disk from the spot indicated 
by Leverrier. 

It is but justice to young Adams to add, that 
after the discovery of this planet by Prof. Galle, he 
perfected his own calculations, and arrived at results 
almost identical with those of the French mathema- 
tician, although he was entirely unknown to him, and 
had pursued an independent train of reasoning. The 
brilliant discovery of this planet was the result of 
pure mathematical calculations, and fully demonstrates 
the power of the human intellect to comprehend the 
laws of nature. Far sweeping in the depths of space, 
unseen by mortal eyes, this new world pursued its 
solemn journey, reflecting back the light of the solar 
orb, steadily obedient to the grand law of Universal 
Gravitation, which held the old planets true to their 
changing orbits. This planet has received the name 
of Neptune. The news of its discovery spread in 
every direction, and rilled the world with astonish 
3 



22 The Science of Astronomy : 

ment and admiration. Neptune is the mo3t remote 
planet from the sun at present known to astrono- 
mers, — the far-off sentinel of the planetary system. It 
requires 165 of our years to complete a single revolu- 
tion around the sun, at the enormous distance of 
2,750,000,000 miles. Such is the history of one of 
the grandest achievements of the human mind, and 
the world will always be glad to honor the names of 
Leverrier and Adams. 

We now come to the most wonderful discovery in 
modern astronomical science since the planet Neptune 
was added to the solar system. The ancient astron- 
omers never dreamed that the constitution of the 
stars and planets would ever be ascertained. But 
even this astounding success has been achieved, and 
we are now permitted to speak — and speak with con- 
fidence — of " Celestial Chemistry," as made known 
to us by a new science called "Spectrum Analysis." 
By " spectrum analysis " is meant the chemical analysis 
of substances by means of a wonderful instrument 
known as the " Spectroscope.'* If a beam of white sun- 
light is allowed to enter a darkened room through a 
small aperture in the window shutter, and then passed 
through a triangular prism of glass, we find that it is 
separated into the seven colors of the rainbow. 
These, collectively, produce what is called the " Solar 
Spectrum." This may be easily formed by any person 
by procuring a triangular piece of glass, and allowing 
the sunlight to pass through it, when a most beauti- 
ful spectrum can be seen ; or a somewhat similar effect 
may be produced by simply looking through one side 
of the glass toward a strong light. What person has 
not amused himself by looking through the triangular 
glasses of a parlor chandelier, and observing the brilliant 



A Popular Lecture. 23 

colors of the rainbow ? This amusement, on a much 
larger and grander scale, has worked wonders in 
modern science, and enabled the astronomer to solve 
some of the most interesting problems of the skies. 

The discovery of the solar spectrum was made by 
Sir Isaac Newton ; but the beautiful coloring is only 
one part of it. In 1802, the solar spectrum was found 
by Dr. Wollaston to be crossed, at right angles, by a 
large number of dark lines. These have been called 
" Fraunhofer Lines," in honor of Prof. Fraunhofer, 
who mapped the plainest of them with great accuracy. 
In 1859, Prof. KirehofF, a distinguished German phi- 
losopher, discovered the real character of these lines, 
and their important significance respecting the phys- 
ical constitution of the sun, stars, and planets. I now 
invite your attention to this illustration of the solar 
spectrum, which, I hope, will render clear the manner 
in which astronomers are able to ascertain the various 
substances existing in the celestial bodies. Here is 
represented a beam of white sunlight coming into a 
darkened room through a small slit in the window- 
shutter, which, upon passing through a triangular 
glass prism, is separated into seven primary colors. 
If a screen be suitably placed to receive the dispersed 
sunlight, we will find a beautiful rainbow-tinted 
streak, composed of seven colors, arranged in the fol- 
lowing order : Yiolet, indigo, blue, green, yellow, 
orange, red. This brilliant band of colors forms 
what is called the " solar spectrum." I have already 
stated that the " Fraunhofer Lines " observed in the 
solar spectrum are dark. When the light from an arti- 
ficial source is passed through a prism, and its spec- 
trum is examined by the spectroscope, no dark lines 
are visible, but instead of these, there will be seen lines 



24 The Science of Astronomy : 

of various bright and beautiful colors. The color of 
these lines, and their place in the spectrum, depends 
upon the substance from which the light proceeds. For 
example : If the metal sodium be burned in a hot gas 
flame, two bright yellow lines will always appear in 
the yellow part of the spectrum, while the metal potas- 
sium in the flame will always give two lines ; one, of 
a brilliant crimson color in the red end of the spec- 
trum ; the other, a beautiful blue line far up in the 
violet end. It was also discovered that each substance 
burning invariably gave forth its own peculiar system 
of lines. 

Upon these few facts rests the whole science of 
" spectrum analysis." Now, what is very remarkable, 
it was found that the position of these bright lines 
coincided with those of the dark lines in the solar 
spectrum. Here is a diagram of the spectrum given 
by the metal sodium in a vaporous condition. This 
is found to be the quality of a spectrum given by a 
gaseous body. You will here observe the position of 
the two bright lines referred to. In the solar spectrum 
are found two dark lines which occupy the same posi- 
tion as those of sodium. Various other substances 
giving bright lines, are also represented by dark lines 
in the solar spectrum. Now, what intelligence do 
these facts convey to the astronomer i It has been 
found that the dark lines of the solar spectrum indi- 
cate vapors cooler than the sun's mass, which inter- 
cept a portion of its light. Thus arise the dark lines ; 
and the astronomer only wants to know the exact po- 
sition of these lines to ascertain what elements exist in 
the sun. The spectrum of a star also exhibits most 
of the dark lines found in the solar spectrum, which 
indicate that the stars are suns like our own. Most 



A Popular Lecture. 25 

of the nebula and comets give a spectrum of bright 
lines, thus proving beyond a doubt that they are of a 
gaseous nature. By means of the spectroscope, as- 
tronomers have learned that all the celestial bodies 
have nearly one identical constitution, and possess 
many elements which exist and even sustain life upon 
our own world. 

" All are but parts of one stupendous whole, 
Whose body nature is, and God the soul." 

We thus see the vast importance of spectrum anal- 
ysis. By a few mysterious, and at first unattractive 
lines, astronomers have been able to make the most 
wonderful discoveries of modern science. And silently 
these lines will continue to speak to us, and more and 
more intelligently and eloquently as we rise higher 
in the intellectual scale, and become better fitted to 
converse with them. It is from our knowledge of 
spectrum analysis that astronomy will reach us, and 
from the revelations of the spectroscope that the fut- 
ure progress of this science will advance. 

Such have been the glorious achievements of modern 
astronomy. We have traced the wonderful progress 
of the human mind during its long and toilsome strug- 
gle of more than sixty centuries. One barrier after an- 
other has given way to the steady march of astronom- 
ical science, until the human mind, majestic in its 
strength, has mounted step by step up the rocky 
height of its self-built pyramid, from whose lofty sum- 
mit it looks out upon the grandeur of God's universe ! 
The grand results of human investigation cannot fail 
to fill the mind with astonishment, and to demonstrate 
the truthful passage of Scripture, that man has been 
made but a little lower than the angels. These brill- 



26 The Science of Astronomy : 

iant achievements of astronomy have not resulted from 
the labors of any one astronomer. No one astronomer 
has ever grasped enough to accomplish much by him- 
self. But each astronomer has done his own little 
part, all the more thoroughly because it has been so 
small, and the aggregate result is a grand one. What 
tribute can we now pay to the memory of that un- 
known mortal who first resolved to read and compre- 
hend the starry heavens 1 To quote the eloquent lan- 
guage of Prof. Mitchell : " On some lofty peak he 
stood, in the stillness of the midnight hour, with the 
listening stars as witnesses of his vows, and there, con- 
scious of his high destiny, and of that of his race, re- 
solves to commence the work of ages. c Here,' he ex- 
claims, ' is my watch-tower, and yonder bright orbs 
are henceforth my solitary companions. Night after 
night, year after year, will I watch and wait, ponder 
and reflect, until some ray shall pierce the deep gloom 
which now wraps the world.' Thus resolved the un- 
known founder of the science of the stars. His name 
and his country are lost forever. What matters this, 
since his works, his discoveries, have endured for cen- 
turies, and will endure as long as the moon shall con- 
tinue to fill her silver horn, and the planets to roll and 
shine." 

Astronomy is now becoming more popular than ev- 
er before. This is by no means a matter of surprise 
as no other science is doing so much to benefit the 
world at large. If any proof were needed that the 
people of this country are thirsting for astronomical 
knowledge, no greater could be found than the interest 
with which the beautiful comet of 1874 was observed, 
and the remarkable success which attended the popu- 
lar lectures of Prof. Proctor, the eminent English as- 



A Popular Lecture. 27 

tronomer. Night after night, this great scientist 
stood before crowded audiences in our largest cities, 
expounding the grand truths of modern astronomy, 
and rejoicing in his noble work. Astronomy is now 
the most perfect of sciences, and hence, astronomers are 
enabled to predict results with absolute precision thou- 
sands of years before they occur. They announce that 
on such a year, month, day, hour, minute, and second, 
a celestial body will occupy a certain position in the 
heavens. At the time indicated, we point our tele- 
scopes to the place, and at the exact instant, true be- 
yond the accuracy of any time-piece, the orb sweeps 
into view. 

It is not to be expected that all persons who pursue 
this charming study will eventually become celebrated 
astronomers ; but it should be the duty of every vota- 
ry in astronomical science, to record all known phe- 
nomena, to arrange and classify the facts, to discover, 
if possible, the laws which he observes ; and if he 
cannot discover at once the sublime marvels of the 
heavens, he can classify all observations for other as 
tronomers in the future, that they may themselves work 
with better hope of success. The small number of 
votaries in astronomical science should be increased. 
Every other profession is now full, and that of astron- 
omy alone needs more enthusiastic workers. There 
are always certain persons who seem to be prejudiced 
against astronomy. They will not only shun this ex- 
alting science themselves, but even persuade others 
not to study it. Would that such persons could only 
appreciate Tennyson's beautiful lines : — 



28 The Science of Astronomy : 

" Let knowledge grow from more to more, 
But more of reverence in us dwell ; 
That mind and soul, according well, 
May make one music as before, 
But vaster." 

If anything seems well calculated to inspire one 
with an emotional love for astronomy, it is certainly 
the magnificent scenery of our nocturnal sky at this 
season of the year. During the autumnal and winter 
months, the starry heavens put on their grandest and 
most attractive appearance. Some of the brightest 
stars in our firmament are at present visible upon the 
evening sky, and great constellations, meandering 
over a large extent of the heavens, continue above our 
horizon throughout the entire night, presenting a 
scene beautiful beyond description. 

<l Thus monstrous forms, o'er heaven's nocturnal arch 
Seen by the sage, in pomp celestial march ; 
See Aries there his glittering bow unfold, 
And raging Taurus toss his horns of gold ; 
With bended bow the sullen Archer lowers, 
And there Aquarius comes with all his showers : 
Lions and Centaurs, Gorgons, Hydras rise, 
And gods and heroes blaze along the skies." 

Compared with the grand appearance of our even- 
ing sky at this season of the year, the most resplen- 
dent terrestrial scenes sink into nothingness, and ap- 
pear unworthy of being set in competition with the 
glories of the starry heavens. 

Do you now ask what is the practical utility of as- 
tronomical science? Many of the benefits derived 
from astronomical observations are perhaps too appar- 
ent in our day to need much explanation before an 
intelligent audience. Independently of the sublimity 
of its objects, and the pleasure arising from their con 



A Popular Lecture, 29 

templation, astronomy is a study of vast utility, in con- 
sequence of its connection with the terrestrial arts and 
sciences, many of which are indebted to the observa- 
tions and the principles of this science for that degree 
of perfection to which they have attained. Prof. 
Steele makes the following impressive remarks, con- 
cerning the value of the stars in practical life : "The 
stars are the landmarks of the universe. They seem 
to be placed in the heavens by the Creator, not alone 
to elevate our thoughts, and expand our conceptions of 
the Infinite and Eternal, but to afford us, amid the 
constant fluctuations of our own earth, something un- 
changeable and abiding. Every landmark about us is 
constantly changing, but over all shine the ' eternal 
stars,' each with its place so accurately marked that 
to the geographer and astronomer no deception is pos- 
sible. To the mariner, the heavens become a dial- 
plate, the figures on its face set with glittering stars, 
along which the moon travels as a shining hand that 
marks off the hours with an accuracy that no clock 
can ever rival. ... In all the intricacies of survey- 
ing, the stars afford the only immutable guide. Our 
clocks vainly strive to keep time with the celestial host. 
Thus, by a wise provision of Providence, even in the 
most common affairs of life, are we compelled to look 
for guidance, from the shifting objects of earth, up to 
the heavens above." 

The great practical purpose of astronomy to the 
world consists in enabling us safely to navigate the 
ocean. Astronomy has proved of indescribable bene- 
fit to the navigator ; for, without some knowledge of 
this science, he never could have traced his course 
over the great ocean to any far-distant land. It is of 
vast importance for the mariner to know on what part 



30 The Science of Astronomy : 

of the globe he is situated at any time in the mighty 
ocean ; also to understand the exact direction in 
which he is sailing. These particulars can be deter- 
mined only by astronomical observations of the utmost 
accuracy. 

Astronomy has also been of great utility to the sci- 
ence of geography ; for without a certain knowledge 
of the heavens, the true figure of our globe would 
never have been ascertained. The manner in which 
Columbus discovered the roundness of the earth was by 
observing its shadow during an eclipse of the moon. 
Before that time, most persons believed that the earth 
was a smooth and boundless plain, and that if its limit 
could be reached, they would fall into what was termed 
the "abyss of tartarus." But to-day the mighty 
ocean is traversed by steam and sail, and commerce is 
carried on in all parts of our civilized world. 

Even religion has been greatly benefited by as- 
tronomy, without a knowledge of which missionaries 
would never have been carried across the ocean to 
teach the heathen and other uncivilized people of the 
existence of a God. If any persons wish to be thorough- 
ly convinced that a Divine Power does rule supreme, 
they need only direct their eyes upward to the noc- 
turnal sky; for there is no better evidence of the ex- 
istence of an Almighty Creator, than the precise 
structure and management of our starry heavens. 

" View the amazing canopy ! 

The wide, the wonderful expanse ! 
Let each bold atheist agree 

That God is there, unknown to chance. " 

Truly, "An undevout astronomer is mad." The 
study of astronomy is direct intercourse with the 



A Popular Lecture. 31 

Master Mind, and the earnest devotee of this sci- 
ence is prepared to " look through nature up to nat- 
ure's God/' 

Let us now consider some of the wonders of astro- 
nomical science. To those who have given but little 
attention to the study of astronomy, many of the great 
facts which I am about to state, will doubtless seem 
astonishing and almost incredible. I will first invite 
your attention to the wonders of the sun, — the great 
fountain of life, light, and heat of our planetary sys- 
tem. The diameter of this great orb is 850,000 miles. 
You will perhaps be able to understand these figures 
better by comparison. In this illustration, the larger 
circle is intended to represent the shell of the sun. 
Now, if we imagine our earth placed here at the cen- 
ter of the sun, there would be enough space for the 
moon to revolve in its regular orbit, represented by 
this circle, within the sun's circumference, besides 
leaving 200,000 miles in every direction beyond. 
The volume of the sun is 1,245,000 times that of our 
earth ; that is, it would require 1,245,000 earths to 
make a globe equal in size to that of the sun. The 
mass of the sun is 674 times that of all the other 
members of the solar system taken together. Recent 
calculations from observations of the transit of Yenus, 
show that the distance of the sun from our earth is 
about 90,000,000 miles. Light, which travels with 
the almost inconceivable velocity of 183,000 miles 
every second, requires 8^ minutes to reach us from 
the sun. If an express train could start from the sun, 
and travel night and day, at the rate of thirty miles 
an hour, it would require 340 years to reach our earth. 
Prof. Proctor says that if an infant were born, having 
an arm 90,000,000 miles long, so as to reach the sun ; 



32 The Science of Astronomy : 

and if, in the cradle, he were to lift out his arm and 
touch this luminary, that infant might grow to the 
threescore years and ten allotted to man, but he never 
would be conscious of the fact that the tip of his finger 
was burned. He would have to live 135 years before 
that would be experienced. Perhaps it would be well 
for some infant to try this just once, to see if the 
professor is correct ! 

The distance of the sun seems enormous to us ; yet, 
it is used by astronomers as a unit for expressing celes- 
tial distances ! We receive enough heat from the sun 
annually to melt a solid layer of ice 38 yards in thick- 
ness, extending over the whole earth. Sir John Her- 
schel says, that if a solid cylinder of ice, 45 miles in 
diameter, and 200,000 miles long, were plunged, end 
first, into the sun, it would melt in a single second of 
time. This glowing orb, which appears so small to us, 
is the scene of tremendous activity. Here on earth 
we sometimes witness fearful tornadoes ; but there are 
atmospheric disturbances taking place on the sun, 
compared with which those of our earth are utterly 
insignificant. Is it a wonder, then, that persons once 
worshiped the sun, that great luminary whose rays 
bring so many blessings to us, and without which all 
life would cease to exist? 

" Great source of day ! best image r here below 
Of thy Creator, ever pouring wide. 
From world to world, the vital ocean round, 
On nature write, with every beam, His praise. " 

If these facts relating to the sun seem astonishing 
to you, the wonders of the star-depths will seem still 
more so. To ordinary vision, the stars appear at rest 
in our heavens ; nor can the astronomer himself rec- 
ognize any signs of motion save by patient and long- 



A Popular Lectun . 33 

continued observation. But every star in the firma- 
ment is on its journey, and moving through space with 
wonderful velocity. Absolute rest is unknown through- 
out the material universe. " There is a great process 
of change going on all around." Our own earth is 
moving with us constantly and rapidly in its orbit. 
Eighteen miles an hour, — no, eighteen miles per sec- 
ond, with nearly every btat of the pulse ! This is our 
velocity as reported by the astronomers ; while we 
sleep seven hours, the world on which we dwell moves 
-±70,000 miles ! It is believed by many astronomers 
that the sun, with its family of planets and comets, is 
moving through space toward the constellation Her- 
cules ! Our entire universe of stars is constantly un- 
dergoing vase changes, which will be perceptible to 
those who inhabit the earth in future centuries. The 
configurations of our starry heavens will eventually 
be greatly changed from their present appearance. 
Orion will then no longer hold supremecy over the 
constellations. The well-know " Big Dipper " will 
sometime, in the distant future, assume a different ap- 
pearance from that now presented to our view, and 
must finally cease to attract the attention of thousands 
who to-day admire its beauty in our northern skies. 
One of the most notable examples of the changes 
taking place in our firmament, is to be found in the 
motions of the seven bright stars forming the "Big Dip 
per," in the constellation Ursa Major. Here is a dia- 
gram showing the stars of the " Big Dipper " in their 
present position. These little arrows indicate the di- 
rection in which the stars are moving, and these dot- 
ted lines show the outline of the " Big Dipper," with 
which you are all familiar. You will observe that 
five of these stars are moving in the same direction, 



34 The Science of Astronomy : 

which shows that they are in some manner associated 
with each other. By a careful study of the motions 
of all these stars, Prof. Flammarion has been able to 
represent the outlines formed by them at various 
times in the past, and those which they will form in 
the distant future. One hundred thousand years ago, 
according to his calculations, the stars forming the 
" Big Dipper " were arranged in the outline of a large 
and irregular-shaped cross, the appearance of which is 
represented in this middle diagram ; and one hundred 
thousand years hence, they will assume the outline of 
an elongated and inverted " Dipper," represented in 
this lower diagram, which will stretch over a large ex- 
tent of the sky. 

The notions hitherto entertained as to the stars and 
the heavens, are destined to undergo a complete revo- 
lution. There are no " fixed stars." Each one of 
those distant suns, flaming in infinitude, is swept 
along in a stupendous movement, which the imagina- 
tion can hardly conceive ; and your humble servant 
ventures to predict, that before many years have 
elapsed, there will be recognized among the stars a 
variety of constitution, and complexity of arrange- 
ments, strikingly contrasted with the general uni- 
formity of structure, at present taught in most of our 
text-books on astronomy. 

"Roll on, ye stars; exult in youthful prime; 
Mark with bright curves the printless steps of Time ; 
Near and more near your beamy cars approach, 
And lessening orbs on lessening orbs encroach. 
Flowers of the sky, ye, too, to age must yield, 
Frail as your silken sisters of the field. 
Star after star from heaven's high arch shall rush, 
Suns sink on suns, and systems systems crush, 
Headlong, extinct, to one dark center fall, 
And death, and night, and chaos mingle all; 



A Popular Lecture. 35 

Till o'er the wreck, emerging from the storm, 
Immortal nature lifts her changeful form, 
Mounts from her funeral pyre, on wings of flame, 
And soars and shines, another and the same." 

The problem which astronomers have to solve in 
ascertaining the distances of the stars, is one of stu- 
pendous difficulty. Of the thousands of stars which 
have been studied, astronomers know the distances of 
only twenty. The nearest star is so remote that its 
light requires 3 J years to reach us, while the light of 
the pole-star is 50 years in reaching us from that 
distant orb ; so that if the light of this star was ex- 
tinguished to-day, 50 years would have to elapse be- 
fore we should be aware of the fact ! There are stars 
so remote that their light cannot reach us in less than 
10,000 years. To traverse the Milky Way, of which 
our own solar system forms a part, light requires 
15,000 years; and to reach us from some of the dis- 
tant nebulae, it must travel for 300 times that period, 
or nearly 5,000,000 years ! It is in the contempla- 
tion of such facts as these, that we fully realize our 
own insignificance in the scheme of creation, and feel 
prepared to exclaim, with the Psalmist : " When I 
consider Thy heavens, the work of Thy fingers, the 
moon and the stars which Thou hast ordained, what is 
man that Thou art mindful of him 1 and the son of 
man that Thou visitest him 1 " 

In concluding my lecture, would it not be well to 
lift the vail which shrouds us from futurity 1 With 
boldness, yet with humility and reverence, let us pro- 
ceed to do so. Who can tell what glorious discoveries 
will have been made in astronomical science after 
another period of six thousand years has rolled 
slowly away 1 Looking into the distant future, 



36 The Science of Astronomy. 

through the dim vista of years, we can, in imagination, 
picture to ourselves the patient astronomer, still at 
his task, watching and waiting, and grappling with 
the grand problems of the skies. We are apt to dis- 
miss reflections of this nature, thinking that but 
very little remains for the astronomer to accomplish. 
But even now, hundreds of grand problems are pre- 
sented to astronomers for solution which escape their 
notice ; and before another century has rolled away, 
in thousands of lofty observatories, with their gi- 
gantic telescopes peering heavenward, there may yet 
be made some of the most brilliant discoveries ever 
chronicled in the annals of astronomical science. 
The watch-towers of the heavens now cover the whole 
earth, and the sentinels never sleep. No star, or 
cluster, or constellation can ever set. It escapes the 
scrutinizing gaze of one astronomer, only to meet the 
equally piercing glance of another. Hark ! from out 
the distant star-depths, and the highways of the 
planets, eastward, westward, northward, southward, 
peals the solemn mandate, " Onward S " This is the 
watchword, and the time is coming, when the true 
astronomer, in his search after the key which unlocks 
the hidden mysteries of the universe, will be able to 
exclaim, in triumph, " Eureka. ! " 
Battle Creek, Mich., Feb. 8, 1877. 




LIBRARY OF CONGRESS 



003 630 109 



